1. Field of the Invention
The present invention relates to a die assembly for molding a cylindrical body, such as a movable lens barrel or the like, and also relates to the cylindrical body produced by the molding die assembly.
2. Description of Related Art
A cylindrical body, for instance, of which a zoom lens barrel for a zoom lens camera is made, is molded by an injection molding process using a die assembly. In this case, the finished molded product (i.e. the cylindrical body) has a parting line which appears on the outer peripheral surface thereof. In general, this parting line, which corresponds to a connecting line between a plurality of split dies, extends in a direction parallel with the optical axis of the lens barrel.
In the case where the cylindrical body is used for a movable lens barrel having a parting line of a certain height extending parallel with the optical axis, a light intercepting member, which optically intercepts light in a gap between the movable lens barrel and an outer ring provided on the outer peripheral surface thereof, can be partly deformed or deflected by the parting line, thus resulting in the formation of a clearance between the movable lens barrel and the outer ring. Since the parting line extends in a direction parallel with the optical axis, as mentioned above, the clearance caused by the deformation or deflection of the light intercepting member continuously extends in the optical axis direction. In this state, if light is made incident upon the lens barrel from the front, the light partly passes through the clearance into the lens barrel. This would have an adverse influence on the photographing efficiency.